What is an endospore?

An endospore is a thick-walled spore produced by certain types of bacteria, allowing them to survive in harsh environmental conditions. This protective structure enables the bacteria to withstand extremes of temperature, desiccation, and exposure to chemicals that would typically be lethal. When conditions become favorable again, the endospore can germinate and turn back into an active bacterial cell. The formation of endospores is a survival mechanism, which is particularly associated with genera like Bacillus and Clostridium.

The other options describe different biological processes or entities but do not accurately define what an endospore is. Recognizing the distinct characteristics of endospores is crucial for understanding bacterial survival strategies and behaviors in various environments, particularly in fields like microbiology and infection control.